1911 problem

Brad

Administrator
Staff member
#1
The last few range trips with my 1911 I noticed a new problem with the primers. They started to show primer swipe, sometimes it even raised a burr that caused trouble with the shell holder.

F2CBD62F-B174-4512-B2B3-CBBEC9546FE2.jpeg
Load is a 200 swc from an MP mould, 4.8 gr of Promo, and a Tula LP in mixed brass.

I looked online and found some info making me think it is a recoil spring/firing pin spring issue. Since I had a couple spares of each on hand from Wolff I decided to make a swap. Firing pin springs looked the same but boy was the original recoil spring a bunch weaker and shorter. Getting the recoil spring plug in place took apparent more effort as does racking the slide.

I used a 16# Wolff recoil spring and the extra power firing pin spring that came with it. Will try to get out before snow flys to see if it makes a difference. Hopefully it helps tame brass ejection a bit too.
 

Ian

Well-Known Member
#2
Weak primer cup? Flash hole too small for the primer brisance? Primer hole too LARGE? Some of the Federal .45 brass used lead-free priming compound and the flash holes were a bunch too big for normal loads. Too much chamber pressure, too fast, gets at the primer cup and swages it back into the firing pin recess.
 

Brad

Administrator
Staff member
#3
Used over 5K of these primers already, most in the 45 ACP in this gun. This is a recent development.
I see this on 25-50% of spent cases now.

Will be interesting to see if it goes away or diminishes with the spring change.
 
#8
I had that happen one time when my oal got to long and it was from a pressure spike.
The way I caught it was I had one failure to go into battery and noticed the rifling had kissed the bullet.
That is a quick easy check for you.
 

Brad

Administrator
Staff member
#9
The barrel was throated by Doug over on CB, bullet doesn’t come in contact with rifling at all.
These were even some .451 bullets I tried. Lead city
 

Ian

Well-Known Member
#10
Any chance the neck tension is insufficient on some of the cases causing telescoped bullets from recoil in the magazine and elevated pressure? I blew up a 1911 due to just that, never really noticed any difference in recoil, either, until the stock panels and magazine departed the frame. Going to .451" with soft bullets can cause borderline bullet pull.
 

Brad

Administrator
Staff member
#11
That is something I plan to test this weekend. I will make up a few dummy rounds and cycle thru the action numerous times
 

Longone

Active Member
#12
Just as an FYI, cycling dummy rounds thru the action “numerous” times may cause set back of the bullet. When the bullet hits the feed ramp, barrel a few times it usually causes set back. IMHO a better way to check crimp/ neck tension would be to make up a dummy then try to set it back by pushing the bullet against a wood work bench or similar. You should be able to lean pretty hard on the base of the case and not set the bullet back.
 

fiver

Well-Known Member
#13
I would talk to Bill before I got too worked up.

the only way your going to swipe anything like that is if the case is moving sideways.
when in the sequence of firing a round is the case moving.
feeding or ejection...
feeding is a sliding motion where the back of the case would be sliding like that.
but the picture is saying the sliding motion is scraping the primer after the round dent from the firing pin has been made.
I would look real close at the area around the firing pin hole on the bolt face and at the bottom of the bolt too.
the firing pin dent is real shallow indicating this might just be happening before the round is even chambered.
except once again the evidence is saying no.
look at the burr,, it isn't flattened on the edge that would be trapped between the round and the bolt face.

you might have [had] a weak firing pin spring.
but something else is causing the scrape to the back of the primer.
 

Ian

Well-Known Member
#14
Definitely the bench edge test. If they set back its likely going to start in magazine, particularly the bottom 2 or 3 that have been slapped over and over on the nose by recoil by the time it's their turn to glance off the feed ramp and top of barrel on the way into the chamber.
 

Brad

Administrator
Staff member
#15
That is what I want to check for.
If a dummy round doesn’t set back after 5-6 cycles then it sure won’t on a single cycle before firing
 
#16
I also had Doug ream that same barrel shortly after that incident.
I think Ian may be heading down the right road.
I had to adjust my neck tension once I went to powder coating it makes em slippery so they can move around if you are on the edge tension wise.
 
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Pistolero

Well-Known Member
#18
Bench edge check. Part of the reason I use a "too tight" TC.

Unless the firing pin has been replaced recently with a smaller diameter one,
that is a sign of overpressure or soft primer. Used to see it on some .38 Super 'major caliber'
loads back in the day, way too hot loads. Too large an unsupported area of
primer with normal pressure can do it. Firing pins are commonly seen in two
diams, normally 9mm size and .45 ACP size, although lately I have seen smaller
firing pin diams on some .45 cal guns.

Most obvious source of over pressure is too much powder. Any chance that the
powder measure has slipped? After that, bullet pushing in during feeding, as
mentioned, will raise pressures.
Another thing to try is a different brand of primers. May have some ultra
soft ones sprinkled in. Extruding back under normal pressures.

What is flashhole diam on the problem cases compared to others? I have heard
that larger flasholes for lead free primers can cause pressure issues with normal
loads.

Bill
 
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Brad

Administrator
Staff member
#19
Same firing pin as the gun came with. I checked the nose and no problem, it looks good. I was afraid there may have been damage.
Same primers and loads I have been using for the past few years.
It is mixed brass but I am seeing so many of these. This is brass I have fired at least 4-5 times now, never had this before.

I will check the crimp.